cdf
Returns the cumulative distribution function value at k for this binomial distribution.
Gives the probability of observing k or fewer successes. Uses the regularized incomplete beta function for numerical stability rather than summing individual probability masses, which would be slow and imprecise for large trial counts.
Return
the probability of k or fewer successes, in the range [0, 1].
Parameters
k
the number of successes at which to evaluate the cumulative probability.